Mechanism of oleoylethanolamide on fatty acid uptake in small intestine after food intake and body weight reduction

The increase in the prevalence of human obesity highlights the need to identify molecular and cellular mechanisms involved in control of feeding and energy balance. Oleoylethanolamide (OEA), an endogenous lipid produced primarily in the small intestine, has been identified to play an important role in the regulation of animal food intake and body weight. Previous studies indicated that OEA activates peroxisome proliferator-activated receptor-alpha, which is required to mediate the effects of appetite suppression, reduces blood lipid levels, and enhances peripheral fatty acid catabolism. However, the effect of OEA on enterocyte function is unclear. In this study, we have examined the effect of OEA on intestinal fatty acid uptake and FAT/CD36 expression in vivo and in vitro. We intraperitoneally administered OEA to rats and examined FAT/CD36 mRNA level and fatty acid uptake in enterocytes isolated from the proximal small intestine, as well as in adipocytes. Our results indicate that OEA treatment significantly increased FAT/CD36 mRNA expression in intestinal mucosa and isolated jejunal enterocytes. In addition, we also found that OEA treatment significantly increases fatty acid uptake in isolated enterocytes in vitro. These results suggest that in addition to appetite regulation, OEA may regulate body weight by altered peripheral lipid metabolism, including increased lipolysis in adipocytes and enhanced fatty acid uptake in enterocytes, both in conjunction with increased expression of FAT/CD36. This study may have important implications in understanding the mechanism of OEA in the regulation of fatty acid absorption in human physiological and pathophysiological conditions.